More than 20 MPs have written to the Serious Fraud Office asking it to investigate the UK home insulation sector. The letter, seen by The Guardian, alleges widespread misselling, poor installation, and misuse of public money in schemes meant to cut household energy bills.
As reported by The Guardian, the cross-party group of MPs cites evidence of companies installing insulation that later caused damp, mould, and structural damage. Some installations were so poor that households ended up with higher heating costs than before.
What this means for existing grant schemes
The Energy Company Obligation (ECO4) and the Great British Insulation Scheme together channel hundreds of millions of pounds into loft, cavity wall, and solid wall insulation for low-income and fuel-poor households. Ofgem oversees the schemes, but the MPs argue enforcement has been weak.
Documents seen by The Guardian suggest that some installers claimed payments for work that was never completed or was done to such low standards that it failed to meet basic building regulations. The SFO investigation, if opened, would examine whether fraud or false accounting took place.
For homeowners, the immediate effect is likely to be slower processing of grant applications. Ofgem may pause or tighten approvals. The Department for Energy Security and Net Zero told The Guardian it is reviewing compliance. Anyone considering a grant-funded insulation job should expect longer wait times and more paperwork.
Who qualifies, and who doesn’t
ECO4 is available to households receiving certain means-tested benefits, with a household income below £31,000 in England and Wales. The Great British Insulation Scheme is broader, any home with an EPC rating of D or below and a Council Tax band A–D in England can apply.
But the MPs’ letter highlights a specific risk: homeowners who are not on benefits but use the Great British Insulation Scheme may be less protected if work goes wrong. The scheme’s consumer complaint route is through Ofgem or the installer’s warranty, not through a formal ombudsman. If the installer goes bust, the homeowner is stuck.
The catch is that poor installation can make a home harder to heat, not easier. Cavity wall insulation that bridges the wall cavity can transmit moisture, leading to damp. Loft insulation that blocks eaves vents can cause condensation and rot. The Energy Saving Trust warns that incorrectly fitted insulation can reduce a property’s EPC score.
What homeowners should check before any insulation work
Three things matter most: installer accreditation, product guarantees, and a written scope of works. Accredited installers should be registered with the National Insulation Association or the Cavity Insulation Guarantee Agency. CIGA offers a 25-year guarantee on cavity wall insulation, but only if the work is done by a CIGA-registered firm.
The Great British Insulation Scheme requires installers to be TrustMark registered, but TrustMark alone does not guarantee technical competence. Homeowners should ask for a detailed survey report before work starts, including a thermal imaging check if possible.
If an installer refuses to provide a written contract or a guarantee certificate, walk away. The MPs’ letter cites cases where companies took payment and then disappeared. Ofgem can remove non-compliant installers from the scheme, but it does not compensate homeowners directly.
For anyone on ECO4, the local authority or energy supplier should have a complaints process. The Energy Ombudsman can handle disputes if the supplier fails to resolve them. But the ombudsman only covers energy suppliers, not insulation contractors themselves.
What this means in practice: if you are offered a free or heavily subsidised insulation upgrade, treat it like any other home improvement. Get three quotes. Check references. Read the small print on the guarantee. The SFO investigation may take months or years. Your roof and walls need protecting now.
Frequently Asked Questions
Over 20 MPs have asked the Serious Fraud Office to investigate the UK insulation sector over allegations of misselling, poor installation, and misuse of public money. For homeowners, this may lead to slower processing of grant applications under ECO4 and the Great British Insulation Scheme, with Ofgem potentially tightening approvals and increasing paperwork.
ECO4 is for households receiving means-tested benefits with an income below £31,000 in England and Wales. The Great British Insulation Scheme is broader, available to homes with an EPC rating of D or below and Council Tax bands A–D in England. However, non-benefit claimants may have less consumer protection if work goes wrong.
Yes, incorrectly fitted insulation can make a home harder to heat. For example, cavity wall insulation that bridges the wall cavity can transmit moisture and cause damp, while loft insulation blocking eaves vents can lead to condensation and rot. The Energy Saving Trust warns this can reduce your property's EPC score, potentially raising energy costs.
Ensure your installer is accredited with the National Insulation Association or the Cavity Insulation Guarantee Agency (CIGA). CIGA offers a 25-year guarantee on cavity wall insulation, but only if done by a CIGA-registered firm. The Great British Insulation Scheme requires TrustMark registration, but this alone doesn't guarantee technical competence, so get a written scope of works and product guarantees.
If your installer goes bust, you may be stuck, especially under the Great British Insulation Scheme where the consumer complaint route is through Ofgem or the installer's warranty, not a formal ombudsman. For ECO4, similar risks apply if the installer isn't properly accredited, so always use a CIGA-registered firm for cavity wall insulation to protect your 25-year guarantee.
